An apparatus, system, and method for driving an end effector in a surgical instrument are disclosed. The method comprises generating a first ultrasonic drive signal by a generator, actuating the ultrasonic transducer with the first ultrasonic drive signal for a first period, generating a second ultrasonic drive signal by the generator, and actuating the ultrasonic transducer with the second ultrasonic drive signal for a second period, subsequent to the first period. The first drive signal second drive signal are different over the first and second periods. The first and second drive signals define a step function waveform over the first and second periods. The apparatus comprises a generator to couple to an ultrasonic instrument. The system comprises a generator coupled to an ultrasonic instrument comprising an ultrasonic drive system comprising an ultrasonic transducer coupled to a waveguide and an end effector. The ultrasonic drive system resonates at a resonate frequency.